1 //===----------------------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 // Copyright (c) Microsoft Corporation. 10 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 11 12 // Copyright 2018 Ulf Adams 13 // Copyright (c) Microsoft Corporation. All rights reserved. 14 15 // Boost Software License - Version 1.0 - August 17th, 2003 16 17 // Permission is hereby granted, free of charge, to any person or organization 18 // obtaining a copy of the software and accompanying documentation covered by 19 // this license (the "Software") to use, reproduce, display, distribute, 20 // execute, and transmit the Software, and to prepare derivative works of the 21 // Software, and to permit third-parties to whom the Software is furnished to 22 // do so, all subject to the following: 23 24 // The copyright notices in the Software and this entire statement, including 25 // the above license grant, this restriction and the following disclaimer, 26 // must be included in all copies of the Software, in whole or in part, and 27 // all derivative works of the Software, unless such copies or derivative 28 // works are solely in the form of machine-executable object code generated by 29 // a source language processor. 30 31 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 32 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 33 // FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT 34 // SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE 35 // FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE, 36 // ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 37 // DEALINGS IN THE SOFTWARE. 38 39 #ifndef _LIBCPP_SRC_INCLUDE_RYU_COMMON_H 40 #define _LIBCPP_SRC_INCLUDE_RYU_COMMON_H 41 42 // Avoid formatting to keep the changes with the original code minimal. 43 // clang-format off 44 45 #include <__assert> 46 #include "__config" 47 48 _LIBCPP_BEGIN_NAMESPACE_STD 49 50 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI inline uint32_t __decimalLength9(const uint32_t __v) { 51 // Function precondition: __v is not a 10-digit number. 52 // (f2s: 9 digits are sufficient for round-tripping.) 53 // (d2fixed: We print 9-digit blocks.) 54 _LIBCPP_ASSERT(__v < 1000000000, ""); 55 if (__v >= 100000000) { return 9; } 56 if (__v >= 10000000) { return 8; } 57 if (__v >= 1000000) { return 7; } 58 if (__v >= 100000) { return 6; } 59 if (__v >= 10000) { return 5; } 60 if (__v >= 1000) { return 4; } 61 if (__v >= 100) { return 3; } 62 if (__v >= 10) { return 2; } 63 return 1; 64 } 65 66 // Returns __e == 0 ? 1 : ceil(log_2(5^__e)). 67 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI inline int32_t __pow5bits(const int32_t __e) { 68 // This approximation works up to the point that the multiplication overflows at __e = 3529. 69 // If the multiplication were done in 64 bits, it would fail at 5^4004 which is just greater 70 // than 2^9297. 71 _LIBCPP_ASSERT(__e >= 0, ""); 72 _LIBCPP_ASSERT(__e <= 3528, ""); 73 return static_cast<int32_t>(((static_cast<uint32_t>(__e) * 1217359) >> 19) + 1); 74 } 75 76 // Returns floor(log_10(2^__e)). 77 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI inline uint32_t __log10Pow2(const int32_t __e) { 78 // The first value this approximation fails for is 2^1651 which is just greater than 10^297. 79 _LIBCPP_ASSERT(__e >= 0, ""); 80 _LIBCPP_ASSERT(__e <= 1650, ""); 81 return (static_cast<uint32_t>(__e) * 78913) >> 18; 82 } 83 84 // Returns floor(log_10(5^__e)). 85 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI inline uint32_t __log10Pow5(const int32_t __e) { 86 // The first value this approximation fails for is 5^2621 which is just greater than 10^1832. 87 _LIBCPP_ASSERT(__e >= 0, ""); 88 _LIBCPP_ASSERT(__e <= 2620, ""); 89 return (static_cast<uint32_t>(__e) * 732923) >> 20; 90 } 91 92 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI inline uint32_t __float_to_bits(const float __f) { 93 uint32_t __bits = 0; 94 _VSTD::memcpy(&__bits, &__f, sizeof(float)); 95 return __bits; 96 } 97 98 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI inline uint64_t __double_to_bits(const double __d) { 99 uint64_t __bits = 0; 100 _VSTD::memcpy(&__bits, &__d, sizeof(double)); 101 return __bits; 102 } 103 104 _LIBCPP_END_NAMESPACE_STD 105 106 // clang-format on 107 108 #endif // _LIBCPP_SRC_INCLUDE_RYU_COMMON_H 109